Flush cistern problem

[Bodgeitandleggit]

I have a push button fitting on my cistern and the last couple of days the water keeps on running into the pan after a flush . I have lifted the cistern up and the part that the push button tube is connected to......... the valve was loose .. I lifted it out and went to re-connect it but there does not appear to have a twist/lock to keep it in place.. when I hold it down to let the cistern fill up water stops running into the pan but when I replace the lid the tube appears to dislodge it and water starts to run again... is this held in by the water itself or am I missing something and how do I stop it?? the valve has a name on it saying viva...thanks in advance

 

[flameport]

Evidently some part is missing or broken. It might be repairable, but ultimately it will be far less bother to just replace the whole lot:
http://www.screwfix.com/p/fluidmaster-button-cable-dual-flush-bottom-inlet/58353

 

[JacktheFitter]

Your bog has an internal overflow, controlled by a floatvalve, either your floatvalve,(much same as a ballcock) has failed or requires adjustment.

 

[igneous]

Is it a cable mechanism on the flush valve? Anyway my advice would be to replace the flush valve, and possibly the float valve too whilst your at it

 

[JacktheFitter]

Overflowing into pan,so floatvalve not shutting off or overflow height needs adjusting, ,simples.